The present invention relates to the use of a combination of topical pharmaceutical compositions for treating onychomycosis. Onychomycosis refers to a fungal infection of the nail unit, defined as the nail matrix, bed or plate. These compositions include an antifungal agent and a potent tissue softening cream containing an effective amount of urea. These combinations may be topically applied concurrently or non-concurrently. The invention also relates to a kit for convenient use by a patient for treating onychomycosis. The kit includes a packet containing two dosage units of the above compositions, occlusive dressings and a protective gel.
Urea has been long recognized as a cosmetic ingredient in formulations acting as a humectant and moisturizer. High concentrations of urea, such as 40%, are also known to have mild, antibacterial effect. At these strengths the antibacterial effects are said to be similar to those of antibiotics, with the further advantage that all the common organisms are susceptible and the possibility of resistant strains need not be seriously considered. There have been reports of keratolytic activity attributed to urea with the ability at high concentrations to solubilize and denature protein. Concentrated solutions of urea can change the conformation of protein molecules. A striking effect is upon the water-binding capacity of the horny layer of the skin: pieces of normal horny layer, or scales from ichthyotic or psoriatic skin that have been soaked in 30% urea solution take up much more water. This is important because in maintaining the flexibility of the horny layer and the softness of the skin, the water content of the horny layer matters much more than its oil content.
Fungal infections of the nail are notoriously difficult to treat. Traditional, topical therapies cannot penetrate the nail plate, and eradicate the infection in and under the nail bed; they are useful only in milder forms of the disease. Systemic antifungal drug therapy is associated with potentially harmful side effects. Since oral antifungals are distributed throughout the entire body, systemic side effects such as elevated liver enzymes, gastrointestinal disorders and skin rashes are not uncommon and may require expensive medical intervention and laboratory tests.
The present invention relates to methods for treating onychomycosis in humans. These methods include topically administrating to the nail area of a human in need of such treatment a safe and effective amount of an antifungal agent, and a safe and effective amount of a potent tissue softener. More particularly, the method involves concurrent or non-concurrent administration of an antifungal composition, and a potent tissue softening composition, optionally with an occlusive dressing and a protective gel.
Use of topical keratolytics, such as urea, improve drug penetration and effects a chemical debridement of the hypertrophic nail. The occlusive dressing enhances the drug penetration.
Accordingly, a first aspect of the present invention is a method for treating onychomycosis by administering either concurrently or non-concurrently to the nail area of a patient in need thereof: (a) a therapeutically effective amount of a tissue softening composition comprising an effective amount of urea and the balance being dermatologically acceptable excipients; and (b) an antifungal composition comprising a therapeutically effective amount of an antifungal agent and a pharmaceutically acceptable carrier.
The invention also relates to a convenience pack containing an antifungal cream and a cream containing an effective amount of urea for the treatment of onychomycosis.
Accordingly, a second aspect of the present invention is a kit to be used by a patient in need of treating onychomycosis, the kit including (a) a first unit dosage form of a tissue softening composition comprising an effective amount of urea and the balance being dermatologically acceptable excipients; (b) a second unit dosage form of an antifungal composition comprising an antifungal agent and a pharmaceutically acceptable carrier; (c) an occlusive dressing, such as an adhesive toe shield dressing, and (d) a protective gel, such as a petroleum jelly.